Montelukast abrogates prednisolone-induced hepatic injury in rats: Modulation of mitochondrial dysfunction, oxidative/nitrosative stress, and apoptosis.

The aim of this study was to investigate the protective effect of montelukast (MTK) against prednisolone-induced hepatic injury in rats. Twenty-eight male albino rats were categorized into four equal groups. Group I served as the control group; group II: rats orally received prednisolone (5 mg·kg-1 ·d-1 ) for 30 days; groups III and IV: rats orally received MTK at 10 and 20 mg·kg-1 ·d-1 , respectively, simultaneously with prednisolone for 30 days. Serum liver enzymes, hepatic mitochondrial function, oxidative/nitrosative stress, and inflammatory and apoptotic markers were evaluated, and the results were confirmed by histopathological examination. MTK showed significant hepatic protection evidenced by alleviated histological lesion and improvement of mitochondrial function, oxidative/nitrosative stress, and inflammatory and apoptotic changes induced by prednisolone, with more profound protection in higher MTK dose (20 mg·kg-1 ). In view of these findings, we can conclude that MTK may have hepatoprotective potential, beyond its therapeutic value for asthmatic patients during their course of corticosteroid therapy.

Ameliorative Effect of Quercetin on Neurochemical and Behavioral Deficits in Rotenone Rat Model of Parkinson's Disease: Modulating Autophagy (Quercetin on Experimental Parkinson's Disease).

Autophagy is necessary for neuronal homeostasis and its dysfunction has been implicated in Parkinson's disease (PD) as it can exacerbate endoplasmic reticulum (ER) stress and ER stress-induced apoptosis. Quercetin is a flavonoid known for its neuroprotective and antioxidant effects. The present study investigated the protective, autophagy-modulating effects of quercetin in the rotenone rat model of PD. Rotenone was intraperitoneally injected at dose of 2 ml/kg/day for 4 weeks. Simultaneous intraperitoneal injection of quercetin was given at a dose of 50 mg/kg/day also for 4 weeks. Neurobehavioral changes were studied. Oxidative/antioxidant status, C/EBP homologous protein (CHOP), Beclin-1, and dopamine levels were assessed. DNA fragmentation and histopathological changes were evaluated. This research work revealed that quercetin significantly attenuated rotenone-induced behavioral impairment, augmented autophagy, ameliorated ER stress- induced apoptosis with attenuated oxidative stress. From the current study, quercetin can act as an autophagy enhancer in PD rat model and modulates the microenvironment that leads to neuronal death.

Modulatory effects of resveratrol on endoplasmic reticulum stress-associated apoptosis and oxido-inflammatory markers in a rat model of rotenone-induced Parkinson's disease.

The mechanisms leading to neuronal death in Parkinson's disease (PD) are not fully elucidated; however, mounting evidence implicates endoplasmic reticulum (ER) stress, oxidative damage, and inflammatory changes are the crucial factors in its pathogenesis. This study was undertaken to investigate the modulatory effects of resveratrol on ER stress-mediated apoptosis, inflammatory and oxidative stress markers in a rat model of rotenone-induced PD. mRNA expression levels of ER stress markers; C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78), were estimated in the rat brain using quantitative real-time PCR. Caspase-3 activity, IL-1ß levels and Nuclear Factor Erythroid 2-related factor (Nrf2) DNA-binding activity were estimated by ELISA, while glutathione peroxidase and Xanthine oxidase activities, as well as protein carbonyl contents in the rat brain were evaluated spectrophotometrically. Our data revealed that Resveratrol ameliorated rotenone-induced ER stress by downregulating CHOP and GRP78 genes expression and hampered caspase-3 activity in the brain of rotenone exposed rats. It also restored redox balance as evident by suppressing Xanthine oxidase activity and protein carbonyls formation; in addition to preservation of intracellular antioxidants status via activating glutathione peroxidase and Nrf2 signaling pathway. In conclusion; our study launched promising avenues for the potential use of resveratrol as a neuroprotective therapeutic agent in Parkinson's disease.

Antidepressant-like effects of Δ9-tetrahydrocannabinol and rimonabant in the olfactory bulbectomised rat model of depression.

The endocannabinoid signalling system is widely accepted to play a role in controlling the affective state. Plant cannabinoids are well known to have behavioural effects in animals and humans and the cannabinoid CB(1) receptor antagonist rimonabant has recently been shown to precipitate depression-like symptoms in clinical trial subjects. The aim of the present study was to investigate the behavioural and neurochemical effects of chronic administration of Δ9-tetrahydrocannabinol (THC) and rimonabant on intact and olfactory bulbectomised (OB) rats used as a model of depression. As expected, OB rats were hyperactive in the open field. Repeated THC (2 mg/kg, i.p. once every 48 h for 21 days) and rimonabant (5 mg/kg, i.p. once every 48 h for 21 days) reduced this hyperactivity, which is typical of clinically effective antidepressant drugs. In intact animals, chronic THC increased brain derived neurotrophic factor (BDNF) expression levels in the hippocampus and frontal cortex but rimonabant had no effect. Rimonabant increased the levels of phosphorylated extracellular signal regulated kinases (p-ERKs(1/2)) in the hippocampus and prefrontal cortex and THC also increased expression in frontal cortex. OB did not affect BDNF or p-ERK(1/2) expression in the hippocampus or frontal cortex and in, contrast to the intact animals, neither THC nor rimonabant altered expression in the OB rats. These findings indicate antidepressant-like behavioural properties of both THC and rimonabant in OB rats although additional studies are required to clarify the relationship between the chronic effects of cannabinoids in other pre-clinical models and in human depression.

Anxiogenic-like effects of chronic cannabidiol administration in rats.

RATIONALE: Several pre-clinical and human-based studies have shown that acutely administered cannabidiol (CBD) can produce anxiolytic-like effects OBJECTIVES: The present study investigated the effects of chronic administration of CBD on rat behaviour and on the expression of brain proteins. METHODS: Male Lister-hooded rats (150-200 g, n = 8 per group) received daily injections of CBD (10 mg/kg, i.p.) for 14 days. The rats were subjected to two behavioural tests: locomotor activity and conditioned emotional response (CER). The expression of brain-derived neurotrophic factor (BDNF), its receptor tyrosine kinase B (Trk B), extracellular signal-regulated kinases (ERK1/2) and phospho-ERK1/2 and the transcription factor cyclic AMP response element binding protein activation (CREB) and phospho-CREB were determined in brain regions such as the frontal cortex and hippocampus using Western immunoblotting. RESULTS: CBD significantly increased the time spent freezing in the CER test with no effect on locomotor activity. CBD significantly reduced BDNF expression in the hippocampus and frontal cortex with no change in the striatum. In addition, CBD significantly reduced TrkB expression in the hippocampus with a strong trend towards reduction in the striatum but had no effect in the frontal cortex. In the hippocampus, CBD had no effect on ERK1/2 or phospho-ERK2, but in the frontal cortex, CBD significantly reduced phospho-ERK1/2 expression without affecting total ERK. CONCLUSION: Chronic administration of CBD produced an anxiogenic-like effect in clear opposition to the acute anxiolytic profile previously reported. In addition, CBD decreased the expression of proteins that have been shown to be enhanced by chronic treatment with antidepressant/anxiolytic drugs.

The effects of chronic administration of tranylcypromine and rimonabant on behaviour and protein expression in brain regions of the rat.

Recent findings indicate that CB1 receptor blockade might be relevant to the action of antidepressant drugs as inhibition of endocannabinoid function can increase synaptic availability of neurotransmitters; an effect also seen with chronic antidepressant drug treatment. Chronic treatments with established antidepressants also lead to raised brain BDNF levels. The aim of this study was to compare the effects of rimonabant (an inverse agonist/antagonist of CB1 receptors) with those of the antidepressant tranylcypromine (TCP), on behaviour and expression of BDNF/CREB signalling pathways in rat brain. Daily (i.p.) injections of vehicle or TCP (10 mg/kg) or rimonabant (2 mg/kg) were given for 14 days. Locomotor activity (LMA) and a conditional emotional response (CER) were measured in addition to levels of BDNF and CREB/phospho-CREB, using immunoblotting, in the frontal cortex, hippocampus, striatum and cerebellum. The velocity of movement was increased significantly on the 3rd, but not 9th, day of TCP treatment versus vehicle-treated rats (p<0.05) while rimonabant had no effect. There were no significant changes in grooming or freezing behaviours after rimonabant or TCP compared to vehicle-treated rats. Rearing was significantly reduced by TCP treatment on the 3rd, but not 9th, day of treatment (p<0.001) while rimonabant had no effect. BDNF levels were significantly increased in the frontal cortex after TCP (p<0.05) but not by rimonabant. Neither TCP nor rimonabant significantly affected CREB or p-CREB expression. In conclusion, chronic administration of TCP to rats increased BDNF expression in the frontal cortex but no similar effect was observed with rimonabant indicating that rimonabant does not show antidepressant drug-like responses after chronic treatment.